<block name="body">
  <notempty name="category">
    <select name="category_id" id="J_category_id">
      <option value="0">请选择文章分类</option>
      <volist name="category" id="vo">
        <notempty name="vo._">
          <optgroup label="{$vo.name}"></optgroup>
          <volist name="vo._" id="vl">
            <option value="{$vl.id}">&nbsp;&nbsp;&nbsp;&nbsp;{$vl.name}</option>
          </volist>
        <else/>
          <option value="{$vo.id}">{$vo.name}</option>
        </notempty>
      </volist>
    </select> 
  </notempty>
</block>
